Catalytic dewaxing

ABSTRACT

A waxy hydrocarbon oil feed is catalytically dewaxed in the presence of hydrogen at dewaxing conditions using a catalyst comprising molybdenum and combined fluorine, calculated as fluorine, in association with a porous solid carrier.

United States Patent HEAVY FEED HYDROCRACKER LIGHT GASES [56] References Cited UNITED STATES PATENTS 2.987.466 6/1961 Sengcr et a1. 208/611 3,268,439 8/1966 Tupman ct a1. H 208/112 3,369,995 2/1968 Tupman ct a1 208/111 Primary Examiner-Herbert Levine Attorneys-A. L. Snow, F. E. Johnston, Charles .1. Tonkin and Roy H. Davies ABSTRACTz A waxy hydrocarbon oil feed is catalylically dewaxed in the presence of hydrogen at dewaxing conditions using a catalyst comprising molybdenum and combined fluorine, calculated as fluorine, in association with a porous solid carrier,

GASOLINE 180' 300 F. J a

JET FUEL FRACTIONATOR WAXY DISTILLATE soo' 100 F.

CATALYTIC DEWAXING INTRODUCTION This invention relates to dewaxing of hydrocarbon oils, and particularly to catalytic dewaxing of hydrocarbon oils.

PRIOR ART Dewaxing of hydrocarbon oils is well known in the art and refers to the treatment of waxy hydrocarbon feeds to reduce the waxy constituents therein. The waxy components of hydrocarbon oils, particularly long chain normal paraffins, impart, for many purposes, undesirable characteristics to the oils and hence must generally be removed, e.g., by solvent dewaxing or, alternatively, converted to nonwaxy components, e.g., by catalytic dewaxing, in order to produce commercially useful products. In particular, hydrocarbon oils having high concentrations of waxy components generally have higher freeze pointsor pour points than oils having lower concentrations of waxy components. For many purposes it is desirable to have oils with low freeze points or pour points. Thus, for example, the lower the freeze point of a jet fuel, the more suitable it will be for operations under conditions of extreme cold. Thus, the fuel will remain liquid and flow freely without external heating even at very low temperatures. In the case of lubricating oils, it is desirable that the pour points be low, thereby enabling the oil to pour freely and adequately lubricate, even at low temperatures. While the freeze point is generally used in reference to jet fuels and the pour point used in reference to diesel fuels and lubricating oils, the process for lowering the freeze point or the pour point, as the case may be, is commonly referred to as dewaxing.

Several processes are available in the prior art for dewaxing hydrocarbon oils. A particularly well known process for dewaxing lubricating oils is solvent dewaxing wherein a solvent such as a mixture of methylethylketone and benzene is added to the waxy hydrocarbon oil. The mixture of methylethylketone and benzene preferentially dissolves the nonwaxy hydrocarbons, thereby permitting separation of the nonwaxy hydrocarbons from the waxy hydrocarbons by cooling and filtration. Another known process is catalytic dewaxing, wherein the waxy components, which are primarily long chain paraffins, are converted in the presence of a catalyst, primarily by isomerization and cracking reactions, to smaller chain and/or branch chain paraffins. Catalytic dewaxing possesses the advantage in that separation of waxy and nonwaxy components is not required.

STATEMENT OF INVENTION It has now been discovered that catalytic dewaxing can be accomplished advantageously using a catalyst comprising a porous solid support in association with molybdenum and combined fluorine. The presence of fluorine with the molybdenum causes a significant improvement in the catalyst. Thus, in the case of catalytic dewaxing of a jet fuel with a catalyst comprising molybdenum and fluorine, a significant improvement in freeze point lowering is obtained compared to catalytic dewaxing at. similar conditions with a molybdenum catalyst not containing fluorine.

In a preferred embodiment of the process of the present in vention, a waxy hydrocarbon oil feed is catalytically dewaxed by contacting the feed and hydrogen at dewaxing conditions in the presence of a catalyst comprising 1 to 18 weight percent molybdenum and 0.1 to 2.0 weight percent combined fluorine, calculated as fluorine, in association with a porous solid carrier.

In another embodiment of the present invention, the waxy hydrocarbon feed is contacted with the catalyst of the present invention in a dewaxing zone to significantly dewax the feed and then the dewaxed product is contacted in a dehydrogenation zone with a dehydrogenation catalyst having essentially no cracking activity to produce hydrogen from the naphthenic hydrocarbons in the dewaxed product.

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DRAWING The present invention will best be understood, and objects and advantages thereof will be apparent, from the following description when read in connection with the accompanying drawing.

The drawing illustrates schematically a particular embodiment of the process of the present invention.

DESCRIPTION OF INVENTION The catalyst used in the catalytic dewaxing process of the present invention comprises molybdenum and combined fluorine in association with a porous solid carrier. The porous solid carrier or support can include a large number of materials with which the catalytically active amounts of molybdenum and fluorine can be associated. The porous solid carrier can be, for example, silicon carbide, charcoal or carbon. Preferably the porous solid carrier is an inorganic oxide. A high surface area inorganic carrier is particularly preferred, for example, an inorganic oxide having a surface area of from 50 to at least 700 mflgm. The carrier can be a natural or a synthetically produced inorganic oxide or combination of inorganic oxides. Typical acidic inorganic oxide supports which can be used are the naturally occurring aluminum silicates and the synthetically produced cracking supports, such as silicaalumina, silica-zirconia, silica-alumina-zirconia, silica-magnesia, silica-alumina-magnesia, and crystalline zeolitic aluminosilicates. Generally, however, it is preferred to use catalysts having low cracking activity, i.e., catalysts of limited acidity. Hence, preferred carriers are inorganic oxides such as magnesia and alumina, particularly high-purity alumina.

A particularly preferred catalytic carrier for purposes of this invention is alumina. Alumina which is satisfactory for the purpose of this invention can be prepared by a variety of methods. The preparation of alumina is well known in the prior art. Thus the alumina may be prepared as alumina hydrosol, alumina hydrogel, alumina xerogel, alumina monohydrate, sintered alumina, and the like.

The catalyst used in the process of the present invention preferably comprises molybdenum in an amount from about 1 to 18 weight percent and more preferably from about 3 to 15 weight percent, based on the finished catalyst. Concentrations of combined fluorine in the finished catalyst composite are preferably from 0.1 to 2.0 weight percent and more preferably from 0.2 to 1.0 weight percent, calculated as fluorine. It may be desirable to have other metals present with the molybdenum. However, in general, metals which effectively poison or limit the catalytic dewaxing properties of the molybdenum should not be used.

Although the molybdenum can be intimately associated with the porous solid carrier by suitable techniques such as by ion-exchange, coprecipitation, etc., impregnation is preferred. In general, the carrier material is impregnation is preferred. In general, the carrier material is impregnated with an aqueous solution of a decomposable compound of the molybdenum, for example a molybdate, in sufficient concentration to provide the desired quantity of metal in the finished catalyst; the resulting mixture is then heated to remove water.

Following incorporation of the carrier material with molybdenum, the composite is dried by heating, for example at a temperature no greater than 500 and preferably from 200 to 400 F., and then calcined at an elevated temperature of up to 1,200 F., if desired. Calcination temperatures are preferably from 600 to l,200 F., and more preferably from 600 to l,000 F.

The catalyst comprising molybdenum is preferably subjected to a reducing atmosphere at an elevated temperature prior to use in the catalytic dewaxing process. The prereduction is preferably performed in the presence of hydrogen and more preferably in the presence of dry hydrogen. It is preferred that the prereduction be accomplished at a temperature in the range of from 600 to l,300 F., preferably 600 to l,000 F. The prereduction may be accomplished for 0.5 to 6 hours, preferably 3 to 5 hours.

The fluorine can be incorporated onto the catalyst carrier at any suitable stage of catalyst manufacture, e.g., prior to or following incorporation of the molybdenum. In general, the fluorine is combined with the catalyst carrier by contacting the carrier with suitable compounds such as hydrogen fluoride or ammonium fluoride, either in a gaseous form or in a watersoluble form. Preferably, the fluorine is incorporated onto the carrier from an aqueous fluoride solution.

The catalytic dewaxing conditions are dependent in large measure on the feed used and upon the desired extent of lowering of the freeze point, or pour point, as the case may be. Generally the temperature will be within the range of from 700 to 950 F. and preferably from 750 to 900 F. The pressure preferably will be within the range from 500 to 5000p.s.i.g. and more preferably 500 to 2,500 p.s.i.g. The liquid hourly space velocity (LHSV) preferably will be from 0.1 to l and more preferably from 0.3 to 3.

Hydrogen must be present in the reaction zone during the catalytic dewaxing process. Thus hydrogen from an extraneous source may be introduced into the reaction zone. For example, hydrogen produced from a naphtha reforming process may be purified and passed to the dewaxing zone. The hydrogen to feed ratio should be from 500 to 20,000 SCF/bbl. of oil, preferably 1,000 to 20,000 SCF/bbL, and more preferably 2,000 to l0,000 SCF/bbl. Generally, hydrogen will be separated from the product and be recycled to the reaction zone.

The waxy hydrocarbon oil feed which can be catalytically dewaxed by the present process includes jet fuel, middle distillate, and lubricating oil boiling range hydrocarbons. Thus the feed should boil above at least 300 F. For purposes of the present invention, the feed preferably should substantially boil within the range from 400 through 750 F. This range includes the middle distillate, jet fuel, and diesel fuel boiling range materials. Heavier hydrocarbon oils can be used, for example lubricating oils which boil above 650 F. and generally substantially above 750 F.

When treating high-boiling feedstock, particularly lubricating oils which boil above 750 F., it may be desirable to hydrotreat the feed with a hydrocracking denitrification-type catalyst in a hydrocracking denitritication zone to convert organic nitrogen compounds and organic sulfur compounds in the feed to ammonia and hydrogen sulfide. The ammonia and hydrogen sulfide can then be removed from the reaction zone effluent, and the substantially nitrogenand sulfur-free product contacted with the catalyst of the present invention in a catalytic dewaxing zone. As a further modification, the nitrogenand sulfur-free feed from the hydrocracking denitriflcation zone can be hydrogenated with an active hydrogenation catalyst in the presence of hydrogen at a tem perature in the range of, e.g., from 200 to 650 F. and a pressure in the range of, e.g., l,000 to 5,000 p.s.i.g., to substantially convert aromatics to naphthenic products before catalytic dewaxing.

The waxy hydrocarbon feedstock desirably contains at least weight percent of waxy hydrocarbons, more preferably at least l0 weight percent, and most preferably at least percent by weight of waxy hydrocarbons. Waxy hydrocarbons mean any normally solid paraffinic hydrocarbons, and include paraffin wax and microcrystalline wax. Preferably the feed contains at least 5 weight percent of C, normal paraffins, that is at least 5 weight percent of normal pentadecane plus higher-boiling range normal paraffins. it has been realized that the C -lnormal paraffms are the most troublesome waxy components; thus lowering the C, normal paraffin concentration produces significant changes in the freezing point and/or pour point.

The feed to be catalytically dewaxed may contain nitrogen, as organic nitrogen, and sulfur, as organic sulfur. Thus, the feed may be a straight run distillate which has not been reduced in sulfur, i.e., which contains at least l0 p.p.m. sulfur by weight. Generally, however, it is preferred that the feed contain less than about 50 p.p.m. nitrogen by weight, more preferably less than about 40 p.p.m., and less than about l.0 percent sulfur by weight, more preferably less than about 0.5 percent. Feedswhich are not already low in nitrogen and sulfur impurities may be reduced in nitrogen and sulfur by hydrofining and/or hydrocracking the hydrocarbon feeds. As one embodiment of the present process, the feed used in the present invention is a hydrofined waxy hydrocarbon oil or a hydrocracked waxy hydrocarbon oil.

Hydrofming operations for lowering the nitrogen and/or sulfur content of petroleum fractions are generally conducted at a temperature of from 500 to 850 F., a pressure within the range of from 400 to 4,000 p.s.i.g., a liquid hourly space velocity (LHSV), i.e., the flow of hydrocarbon feed to the catalyst, of from 0.2 to 10 volume of feed/volume of catalyst/hour (v./v./hr.) and a hydrogen flow rate of above about 500 SCF/bbl. of feed. Catalysts useful in hydrofining operations include, among others, alumina-containing supports having molybdenum and/or tungsten oxide together with iron, cobalt and/or nickel oxides thereon.

Hydrocarbon oils to be catalytically dewaxed can also be prepared by hydrocracking heavy virgin crudes, vacuum distillate residues, catalytic cycle oils, coker gas oils, etc., followed by fractionation to obtain the desired boiling range material for dewaxing. Hydrocracking is generally accomplished at a temperature of from 450 to 900 F. and a pressure between about 500 to l0,000 p.s.i.g. Preferably, pressures of 1,200 and 6,000 p.s.i.g. are used. The hydrogen flow rate into the reactor is preferably maintained between 1,000 and 20,000 SCF/bbl. of feed, more preferably in the range 4,000 to 10,000 SCF/bbl. Suitable hydrocracking catalysts include silica-containing supports, e.g., silica-alumina, silica-zirconia, silica-alumina-zirconia, crystalline zeolitic aluminosilicates, etc., in association with metals of Group Vl through Vlll as well as the oxides and sulfides thereof, e.g., nickel.

As one embodiment of the present invention, the waxy hydrocarbon feed is catalytically dewaxed at dewaxing conditions and in the presence of hydrogen with a catalyst comprising 1 to l8 weight percent molybdenum and 0.1 to 2.0 weight percent combined fluorine associated with a porous solid carrier to lower the waxy hydrocarbon concentration, then the catalytically dewaxed product is dehydrogenated at dehydrogenation conditions and in the presence of hydrogen with a catalyst having substantially no cracking activity, comprising 0.0l to 3.0 weight percent platinum and 0.1 to l0 weight percent alkali metal or alkaline earth metal in association with a porous solid carrier. The dehydrogenation catalyst substantially dehydrogenates naphthenic hydrocarbons, particularly cyclohexane and alkylcyclohexane compounds, present in the feed. Thus, preferably at least 20 volume percent of the naphthenes are dehydrogenated. Hydrogen which is produced in the dehydrogenation step is preferably recycled to the catalytic dewaxing zone. The hydrogen-containing gas which is recycled to the catalytic dewaxing zone can desirably having H S removed, e.g., by scrubbing. Also, water can be removed as, e.g., by passing the gas through a molecular sieve. The combined catalytic dewaxing and dehydrogenation process is preferably operated with no net consumption of hydrogen. Thus sufiicient hydrogen is produced in both zones to satisfy the requirements for catalytic dewaxing.

The waxy hydrocarbon oil feed containing naphthenic hydrocarbons which is subject to catalytic dewaxing followed by dehydrogenation preferably boils within the middle distillate range, for example in the range from 400 to 750 F. Generally at least 30 volume percent napthenes should be present in the waxy hydrocarbon oil feed in order to operate with no net consumption of hydrogen.

The dehydrogenation catalyst will contain platinum and an alkali or alkaline earth metal in association with a porous solid carrier. The carriers suitable for the dehydrogenation catalyst should be nonacidic porous solid carriers. The term nonacidic" is intended to preclude the use of halogen components and those inorganic oxides which possess the acidic function characteristic of materials which actively promote cracking reactions. Preferably the porous nonacidic solid carrier is an inorganic oxide. The carrier material can be a natural or a synthetically produced inorganic oxide or combinations of inorganic oxide. Supports which inherently have acidic sites which promote cracking reactions must have their acidic sites completely neutralized in order to produce the desirable nonacidic carrier. Alumina is a particularly preferred carrier for the dehydrogenation catalyst.

The dehydrogenation catalyst preferably has disposed thereon an alkali or alkaline earth metal, as such or in the form of a compound, for example lithium, sodium, potassium,

rubidium, cesium, calcium, magnesium, etc. Preferably the carrier has associated therewith an alkali metal, particularly lithium. Sufficient alkali or alkaline earth metal or other neutralizing material should be present to completely neutralize the acidic sites of the carrier plus any other inherent acidity possessed by the dehydrogenating metal, for example platinum. The alkali and alkaline earth metals are present, as such or as metal compounds, generally in an amount, calculated as the metal, of from 0.1 to 20 weight percent based on the finished catalyst, and preferably from 0.] to weight per cent. The carrier should remain effectively neutralized throughout the dehydrogenation process. Neutralization. of acidic sites is preferred even in the case of the relatively nonacidic carriers, for example alumina. Such carriers, although considered to be nonacidic, possess a limited amount of acidity, which is not desirable for purposes of the present invention. Furthermore, platinum possesses a certain inherent acid function, which it is desirable to counteract.

The dehydrogenation reaction may be conducted at a temperature of from 700 to 950 F., a pressure from 500 to 5000 p.s.i.g., and a liquid hourly space velocity of from 0.1 to 10. In the combination process of catalytic dewaxing followed by dehydrogenation, the temperature in the dehydrogenation zone is preferably 25 to 200 higher than the temperature in the catalytic dewaxing zone. The higher temperature permits more effective dehydrogenation of naphthenes. Since the support is nonacidic or has essentially no cracking activity, the increase in temperature does not result in an appreciable increase in cracking.

A particularly preferred embodiment of the present process is illustrated in the drawing. A heavy feed, e.g., a crude petroleum oil boiling within the range of from about 500 to 1,000" F., is fed to hydrocracking unit 1 via line 2. Hydrogen is added to the hydrocracking unit via line 3. Any ofa number of conventional hydrocracking catalysts could be used in hydrocracking unit 1, as for example a Group Vll-metal-con taining silica-alumina catalyst. The heavy feed is converted in the hydrocracking unit to a number oflighter materials. These materials are removed from hydrocracking unit 1 and passed to fractionation zone 4 through line 5 and are there separated into a plurality of streams. Light hydrocarbon gases, particularly C '5 to C '5, and hydrogen are removed from the fractionator through line 6. A gasoline fraction boiling in the range of, e.g., 180 to 300 F., is removed through line 7. The gasoline fraction may desirably be further treated in a naphtha reforming zone where the fraction is contacted with a platinum-alumina catalyst to produce a high-octane gasoline product. A jet fuel cut boiling within the range of, e.g., 300 to 500 F. is removed from the fractionator through line 8. Highboiling products, particularly products boiling above about 700 F., are removed from the fractionator through line 9. These may desirably be recycled to hydrocracking unit 1 or can be further fractionated to recover a lubricating oil cut, the lubricating oil cut being separately treated to increase its usefulness. A waxy distillate boiling within the range from about 500 to 700 F. is removed from fractionator unit 4 through line 10. It is understood that fewer or additional streams could be withdrawn from fractionator 4, depending on the particular needs of the refinery.

The waxy distillate is passed into a reaction vessel 11, which contains in dewaxing zone 12 a bed of molybdenumand fluorine-containing catalyst described above. The waxy distillate is catalytically dewaxed in zone 12 at dewaxing conditions including, e.g., a temperature of 700 to 950 F., a pressure of 500 to 2,500 p.s.i.g., and hydrogen to feed ratio of 500 to 20,000 SCF/bbl. The product emerging from zone 12 has a significantly lower freeze point than the feed to zone 12. The low-freeze point product from zone 12 is then passed in contact with a dehydrogenation catalyst in dehydrogenation zone 13. The dehydrogenation catalyst possesses essentially no cracking activity. A suitable catalyst as described above is platinum and alumina, having lithium in association therewith. Rhenium may also be present on the catalyst. The dehydrogenated product is recovered from reactor 11 and sent to separator 14 through line 15. Hydrogen recovered in separator 14 is recycled to reactor ll by means ofline 16. As an alternate to having the dewaxing catalyst and the dehydrogenation catalyst in the same reactor, two reactors may be used, the dewaxing catalyst in one reactor and dehydrogenation catalyst in the other reactor.

The product recovered from separator 14 is passed to zone 18 via line 17 wherein the oil is separated into a plurality of products, including a low freeze point, 300 to 550 F. jet fuel which is withdrawn from zone 18 through line 19. Other products which can be withdrawn from separator 18 include light gases and hydrogen from line 20, a gasoline cut boiling within the range from 180 to 300 F. from line 21, and a 550 F. material from line 22. The gasoline and 550 F. product may be separately treated. All or a portion of the 550 F. product may be recycled, if desired.

In a preferred embodiment of the process, the jet fuel fraction withdrawn from separation zone 18 through line [9 is combined with the jet fuel fraction withdrawn from fractionator 4 through line 8. Altemately, the dewaxed product from zone 12 may be recovered directly from zone 12 via line 23 without being subjected to dehydrogenation in zone 13, and then fractionated to obtain ajet fuel cut. The resulting jet fuel cut may then be blended with the jet fuel from line 8 to obtain an improved low-freeze point product. Alternately, the dewaxed jet fuel from line 19 or 23 could be combined with a straight run jet fuel; this combination has a synergistic effect on the freeze point, giving the resulting blended jet fuel product an unexpectedly low-freeze point.

[t is preferred to operate the dewaxing and dehydrogenation steps of the process illustrated in the drawing at conditions of no net consumption of hydrogen. Thus it is preferred that no excess hydrogen be added to reactor 11. The conversion of naphthenes to aromatics in zones 12 and 13 resuits in the production of hydrogen, which is recovered from the products in separator 14 and recycled to dewaxing zone 12 through line 16. It is apparent that in order to operate the dewaxing and dehydrogenation zones at no net consumption of hydrogen, the conditions in dewaxing zone 12 and dehydrogenation zone 13 must be suitably controlled so that sufficient hydrogen is produced in zones 12 and 13 to accommodate the needs of zone 12. Thus the dehydrogenation zone is preferably operated at the same pressure as dewaxing zone 12, but at a temperature from 25 to 200 F. higher than the temperature maintained in the dewaxing or isomerization zone 12. The higher temperature permits greater conversion of naphthenes to aromatics; inasmuch as the dehydrogenation catalyst has essentially no cracking activity the higher temperature does not result in significant cracking which consumes hydrogen.

The process of the present invention may be better understood by reference to the following example.

EXAMPLE Separate portions of a 384-566 F. waxy hydrocarbon distillate were catalytically dewaxed separately, using a first catalyst comprising molybdenum and alumina, but no fluorine, and a similar catalyst comprising fluorine. The distillate had a sulfur content of 1,100 ppm, a nitrogen content of 14 p.p.m., and a freeze point of +14 F. The feed contained 52.8 volume percent paraffins, 39.1 volume percent naphthenes and 8.1 volume percent aromatics. The C normal paraffin content was 16.1 weight percent.

Catalyst A, containing no fluorine, consisted of approximately 9 weight percent molybdenum disposed on an alumina carrier. The fluorine-containing catalyst (Catalyst B) comprised 9 weight percent molybdenum and 0.5 weight percent combined fluorine, as fluoride, calculated as fluorine, disposed on alumina.

The results of catalytic dewaxing with the two catalysts are shown in Table I. The reaction conditions of pressure (1,200 p.s.i.g.), liquid hourly space velocity (2.0 v./v./hr.), and hydrogen to feed ratio (6,700 SCF/bbl.) and temperature (857 F.) were the same for the two runs. Once-through hydrogen was used in both cases. The advantages of the catalytic dewaxing process of the present invention are clearly shown in table I. The lowest possible freeze point is the most desirable, and, as can be seen, the process using the fluorinecontaining catalyst produces a product oil which has a freeze point considerably below that of the product oil produced under similar reaction conditions with a molybdenum catalyst without fluorine.

Although only specific embodiments of the present invention have been described, numerous variations can be made in these embodiments without departing from the spirit of the invention, and all such variations that fall within the scope of the appended claims are intended to be embraced thereby.

What is claimed is:

l. A process for catalytically dewaxing a waxy hydrocarbon oil feed which comprises contacting said feed at dewaxing conditions, including a temperature of 700-950 F., a pressure of 500 -5000 p.s.i.g., a liquid hourly space velocity of 0.1 to 10 and a hydrogen to feed ratio of 500 to 20,000 SCF/bbL, in the presence of hydrogen with a catalyst consisting essentially of l-18 weight percent molybdenum and 0.2-1.0 weight percent combined fluorine in association with a porous solid carrier.

2. The process of claim 1 wherein said carrier is a porous inorganic oxide.

3. The process of claim 1 wherein said carrier is alumina.

4. The process of claim 1 wherein said combined fluorine is present in an amount less than 1 weight percent.

5. A process for the conversion of waxy hydrocarbons which comprises contacting a feed containing said hydrocarbons at a temperature of from 700 to 950 F., a pressure of from 500 to 2,500 p.s.i.g., a liquid hourly space velocity of from 0.1 to 10 and in the presence of 500 to 20,000 SCF hydrogen/bbl. of feed, with a catalyst consisting essentially of a porous inorganic oxide carrier in association with from 1 to 18 weight percent molybdenum and 0.2 to 1.0 weight percent combined fluorine, calculated as fluorine.

6. A process for the conversion of a waxy hydrocarbon oil feed containing naphthenic hydrocarbons which comprises contacting said feed at dewaxing condition and in the presence of hydrogen with a catalyst consisting essentially of l to 18 weight percent molybdenum and 0.2 to 1.0 weight percent com ed fluorine to substantially lower the freeze point,

then contacting said low-freeze point product at dehydrogenation conditions and in the presence of hydrogen with a catalyst having substantially no cracking activity comprising 0.01 to 3.0 weight percent platinum and 0.1 to 10 weight percent alkali metal or alkaline earth metal, as such or in the fonn of a compound, in association with a porous inorganic oxide carrier to substantially dehydrogenate said naphthenic hydrocarbons.

7. The process of claim 6 wherein the temperature in said dehydrogenation zone is between 25 to 200 higher than the temperature maintained in said dewaxing zone. 

2. The process of claim 1 wherein said carrier is a porous inorganic oxide.
 3. The process of claim 1 wherein said carrier is alumina.
 4. The process of claim 1 wherein said combined fluorine is present in an amount less than 1 weight percent.
 5. A process for the conversion of waxy hydrocarbons which comprises contacting a feed containing said hydrocarbons at a temperature of from 700* to 950* F., a pressure of from 500 to 2, 500 p.s.i.g., a liquid hourly space velocity of from 0.1 to 10 and in the presence of 500 to 20,000 SCF hydrogen/bbl. of feed, with a catalyst consisting essentially of a porous inorganic oxide carrier in association with from 1 to 18 weight percent molybdenum and 0.2 to 1.0 weight percent combined fluorine, calculated as fluorine.
 6. A process for the conversion of a waxy hydrocarbon oil feed containing naphthenic hydrocarbons which comprises contacting said feed at dewaxing condition and in the presence of hydrogen with a catalyst consisting essentially of 1 to 18 weight percent molybdenum and 0.2 to 1.0 weight percent combined fluorine to substantially lower the freeze point, then contacting said low-freeze point product at dehydrogenation conditions and in the presence of hydrogen with a catalyst having substantially no cracking activity comprising 0.01 to 3.0 weight percent platinum and 0.1 to 10 weight percent alkali metal or alkaline earth metal, as such or in the form of a compound, in association with a porous inorganic oxide carrier to substantially dehydrogenate said naphthenic hydrocarbons.
 7. The process of claim 6 wherein the temperature in said dehydrogenation zone is between 25* to 200* higher than the temperature maintained in said dewaxing zone. 